The Kangaroo industry
Although the rabbit-proof fence was not rabbit proof, it did kill a lot of emus.
Environmental problems in Australia
In 2010, Australia had 1750 native species on the threatened list. 59 mammals were at risk of immediate extinction and 18 mammals had gone extinct in the last 100 years. In contradiction with popular belief, the areas most disconnected from urban activities had the highest rates of extinction. For example, at the 136 sites across northern Australia that had been repeatedly surveyed since 2001, the mammal populations had dropped by an average of 75 per cent. The number of sites classified as ''empty'' of mammal activity rose from 13 per cent in 1996 to 55 per cent in 2009. (1)
The areas experiencing a decline in mammal activity included the world heritage listed Kakadu National Park. From 1990 to 2010, there had been a 71 percent decline in the total number of animals in the park and almost half the area of the national park no longer had any native mammals at all. It must be stressed that, within the National Park, the native animals had not been threatened by farming, had not been threatened by mining, had not been threatened by urban development and had not been threatened by human “neglect.”
The decline in marsupial numbers in Australia can be directly attributed to management policies that purport to be in the interests of the ecosystem but are really just an expression of environmental xenophobia and/or aimed at gaining funding.
The collateral damage of the myxomatosis virus provides one of the better examples of how policies devised in the pursuit of alternative agendas are destroying the ecosystem. Myxomatosis was first released in the Murray Valley in 1950 and originally killed up to 99 per cent of infected rabbits. Over the following decades, myxomatosis was spread Australia wide, and likewise achieved impressive kill rates.
While the virus was great for farming communities, for native ecosystems, the rapid removal of the rabbit caused massive problems in the ecological balance. Large populations of rabbits were sustaining large populations of native birds, quolls and goannas. They were also sustaining large numbers of introduced predators such as foxes and cats. When rabbit populations rapidly crashed due to a myxomatosis outbreak, there was a lag between the decline in rabbit numbers, and the decline in predator numbers that were required for a return to an ecological balance. For example, cat populations will take at least four months to adapt to the crash in rabbit numbers. It is in this four-month lag that the alternative species (such as bilbies, bogals and marsupial mice) were most vulnerable to what has been termed hyper-predatation. In short, large numbers of birds of prey, quolls, goannas, foxes and cats hunted the very few marsupials in the area before dying of starvation themselves.
With time, the rabbits that did not die produced a high level of antibodies, and subsequently passed these antibodies on to the kittens. Whereas the kill rate was once 99 per cent, now it has declined to an overall rate of around 50 per cent, and some rabbit populations are completely immune. Ironically, as rabbits returned to their old stomping grounds, they found the ecosystem infinitely more desirable than the one that they had left. With less predators than there were previously, and few small mammalian competitors, they were able to breed unchecked, and reach plague populations again. Because foxes and cats breed relatively faster than quolls, their numbers were also able to rebound once rabbit numbers rebounded thus making it difficult for quolls to make a comeback as well. In other words, the introduction of myxomatosis contributed to the removal of small marsupials as well as the almost complete domination of cats, foxes and rabbits in the ecosystem.
Aside from myxo, rabbits have also been temporarily eliminated form ecosystems using warren ripping, fumigation, poisoning, and rabbit calicivirus. In each case, there has been short term damage to rabbit numbers for long term damage to other small marsupials. In the early 20th century, there was even a farcical attempt to build a 1,833 km long fence to keep rabbits out of Western Australia. It was quite optimistic thinking to believe that it was ever going to keep out the singular pregnant female that would make it obsolete. Rabbits simply burrowed underneath, went through open gates or the fence was knocked down by camels and the rabbits went over the top. To make matters worse, the fence became a land version of the drift nets of death seen in the oceans. Kangaroos sometimes got their legs caught in the wires and thousands of migrating emus came to the fence and perished.
Failure to see the collateral damage associated with rabbit-eradication programs can be partly attributed to scientists just taking a short term and blinkered view on management; however, it can also be attributed to a value system that ranks animals according to their “right” to be in the ecosystem. Animals with low rights are killed, not because they are not adding value to the ecosystem, but because some humans have decided that they have no right to exist. This value system is in turn aided by funding processes that are often biased towards ideological fashions rather than science.
Aside from rabbit eradication programs, fire management programs have also led to a significant decline in native animals while being justified with some dodgy environmental claims. Fire causes massive damage to the ecosystem by stripping it of its nutrients and water, thus decreasing its productive capacity. Furthermore, when forests start giving way to scrub land as a result of fire, they become even more fire prone as a reduction in decomposition results in a greater build-up of fuel and grass starts to dominate over more luscious trees. In recent years, the fire proneness of Australia has increased even more with the spread of gamba grass from Africa. Gamba grass can produce up to five times the fuel load of native grasses but can recover from fire even faster than eucalypts. Deliberate burning of the bush is therefore helping gamba grass take over much of northern Australia.
In addition to reducing the productivity of the land and making Australia more fire prone, fire kills many of the native predators that can reduce rabbit numbers. Specifically, on Kangaroo Island, goannas have eaten rabbits to extinction. Because they can go down holes, rabbits have little defences against them. On the mainland, goanna numbers are far lower due to the greater prevalence of bushfires and these bushfires are often started by land care managers.
Various justifications have been used for burning the bush. Some scientists have proposed that if patches of an ecosystem are burnt in a "mosaic", biodiversity will be greater in the mosaic than a similar sized plot of land that has not been burnt. If that logic were accepted, then "mosaic logging" should also increase biodiversity as would "mosaic cattle grazing " and "mosaic mining". Perhaps it would be correct but in each case, the biodiversity would come about due to reducing the productive capacity of some parts of the mosaic. As an alternative, if human created environmental mosaics were the best avenues to biodiversity, then "mosaic watering" and "mosaic fertilising" would be superior because they would actually increase the productivity of the land. The greater the producity, the greater the biodiversity.
A final justification to burn the bush is to stop global warming. According to CSIRO research scientist Dick Williams, if an ecosystem is burnt, then it wont suffer extreme bushfires in the future. Therefore, paying people to burn the bush should be seen as a form of carbon trading. American gas company ConocoPhillips agrees, and is now paying people $1 million a year, for 17 years, to offset 100,000 tons of the refinery's own greenhouse emissions. So, according to the company's press-releases, Australians can now be "comforted" in the knowledge that burning ConocoPhillips gas wont cause global warming as Australians are offsetting the damage by burning the local bush.
Although William' logic was transformed into a $1 million revenue stream, it was through selective use of statistics. For example, if each year, 10% of a barrel of oil is removed and burnt, then over 7 years, there will be less carbon released than if the entire barrel was burnt in one year. However, if it is burnt for ten years, then the released carbon would be the same. In short, if two patches of land are still grassland after 10 years, then the amount of carbon released into the atmosphere is the same irrespective of whether one is slightly burnt every year and the other is burnt once deeply every 5 years.
In contrast, if the oil could be turned into a carbon sink forest, then not only would carbon not be released, but carbon would be taken out of the atmosphere. Potentially, this could be achieved by planting non-flammable trees to act as fire breaks and progressively replacing fire prone foliage, such as gamba grass and eucalypts, with less prone varieties that are eaten by animals. Again, burning the bush is an example of human intevention just as is planting exotic species, however, the former reduces productive capacity while the later enhances it.
Aside from planting less fire prone species, another method to reduce the bushfire threat via means other than eradicating vegetion is to allow the feral horses, camels, buffaloe, goats and large populations of kangaroos to remain on the land so they eat the grass that causes fire.
1) Ben Cubby, 20 years left: mammals plunge into extinction September 2, 2010, Sydney Morning Herald http://www.smh.com.au/environment/conservation/20-years-left-mammals-plunge-into-extinction-20100901-14nmz.html
Bush fire prevention